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Influence of particle size on property of Ti-6Al-4V alloy prepared by high-velocity compaction 被引量:7
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作者 闫志巧 陈峰 +1 位作者 蔡一湘 尹健 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第2期361-365,共5页
Three Ti-6Al-4V alloy powders with median diameters of 103, 66 and 44 pm, respectively, were pressed by high-velocity compaction (HVC) technology and then sintered in vacuum. The effects of particle sizes on forming... Three Ti-6Al-4V alloy powders with median diameters of 103, 66 and 44 pm, respectively, were pressed by high-velocity compaction (HVC) technology and then sintered in vacuum. The effects of particle sizes on forming as well as properties of sintered samples were investigated. The results show that fine powders are more difficult to press than coarse powders and its compact density is lower too. But the sintered density of fine powders is obviously higher than that of coarse powders. Compared with the powders with 103 and 66 ~un in diameter, the green density with 44 ~rn diameter powders is lower, which is 85.1% of theoretical density (TD) at an impact energy of 913 J. After sintering at 1300 ~C for 2,5 h, the sintered density of the compacts with 44 pm diameter powders is the highest, and reaches 98.2% of TD. Moreover, the sintered sample with 44 pan in diameter has the highest hardness and compressive strength, which are HV 354 and 1265 MPa, respectively. 展开更多
关键词 TI6AL4V high-velocity compaction (hvc) green density SINTERING
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高速云研究进展
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作者 王向华 林伟鹏 《天文学进展》 CSCD 北大核心 2004年第4期318-333,共16页
1963年通过氢21 cm谱线观测发现了高速云(HVCs),40多年来其起源一直是天文界争论的焦点之一。近几年通过高分辨率观测、理论模型和数值模拟,对其中几类高速云及全天性的研究有了很大突破。主要介绍一些研究进展,包括对新发现的两类致密... 1963年通过氢21 cm谱线观测发现了高速云(HVCs),40多年来其起源一直是天文界争论的焦点之一。近几年通过高分辨率观测、理论模型和数值模拟,对其中几类高速云及全天性的研究有了很大突破。主要介绍一些研究进展,包括对新发现的两类致密高速云和高度电离高速云的总体性及个别性的观测研究;对南天区最大的MS和北天区最大的Complex C的高分辨率观测;唯一确定了Complex A的距离在4-10 kpc之间;利用Hα发射线对高速云的距离作了粗略的限制;而在高速云内寻找恒星的努力都以失败告终。另外还简单介绍了一些试图解释高速云起源的理论模型和数值模拟。 展开更多
关键词 天体物理学 高速云(hvcs) 综述 起源 观测 理论
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